/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number[]}
 */
 var inorderTraversal = function(root) {
    // 逻辑和94相同 可以查看94
    const recursion = function(node){
      if(!node) return
      recursion(node.left)
      res.push(node.val)
      recursion(node.right)
    }
    let res = []
    recursion(root)
    return res
};